1. Field of the Invention
The present invention relates to a method for manufacturing an organic electroluminescence device, and to an electronic apparatus.
Priority is claimed on Japanese Patent Application No. 2004-130867, filed Apr. 27, 2004, the content of which is incorporated herein by reference.
2. Description of the Related Art
Recently, in electronic apparatus such as notebook PCs, mobile phones and personal digital assistances, a display unit such as an organic electroluminescence (hereinafter, referred to as an organic EL) device has been proposed, which includes organic EL elements corresponding to pixels, as a means for displaying information.
One of such organic EL devices is an organic EL device of a passive matrix type. The passive matrix type organic EL device generally includes a plurality of first electrodes extending in a predetermined direction in a strip shape on a substrate, a plurality of second electrodes arranged in a direction orthogonal to the first electrodes, and organic functional layers vertically sandwiched between the first and the second electrodes at intersection areas of the first and the second electrodes. The organic functional layer includes a light-emitting layer which emits light when an electric current flows to the first and the second electrodes, and the passive matrix type organic EL device is formed by including a plurality of organic functional layers including the light emitting layer, corresponding to one pixel.
The second electrode of the passive matrix type organic EL device is generally formed by vacuum evaporation. According to this vacuum evaporation, as is well known (for example, Japanese Unexamined Patent Application, First Publication No. H11-87063), a separator is provided in a predetermined thickness between the areas where the second electrodes are formed, so that the second electrodes are separated from each other by depositing a second electrode material on the surface of the substrate from a vertical direction or an oblique direction. When the organic functional layer is formed by a droplet ejection method, the material of the organic functional layer is ejected on the first electrode exposed between the separators, and dried to form the organic functional layer.
In the conventional method however, there are problems as described below.
In general, when the film thickness is increased when a film is formed by the vacuum evaporation method, the film may peel off due to film stress, or the light-emitting layer may deteriorate due to radiant heat from the deposition source due to long-time film forming. Therefore, the film thickness of a cathode film-formed by the vacuum evaporation method is restricted to a thin film. As a result, the electric resistance of the electrode inevitably increases.
When the electric resistance of the cathode is large, voltage applied to the organic EL device decreases more due to voltage drop, the closer to the center of the display region, thereby causing luminance unevenness. This voltage drop is noticeable particularly in the case of a large organic EL display unit, thereby causing a problem in that the display quality decreases.
Therefore, studies have been made to form the film of the electrode by, for example, a droplet ejection method. The droplet ejection method is for forming a linear electrode by providing a plurality of partitions, leaving a space therebetween, and ejecting and baking droplets including conductive minute particles into a film-forming area between these partitions. According to this method, the electric resistance can be reduced by increasing the film thickness of the electrode, as compared to the deposition method.
In this configuration however, the droplets flow out from the film-forming area, and the adjacent electrodes formed with the partition therebetween may come in contact with each other at the end portions of the partitions in the lengthwise direction. In this case, the electrodes are electrically connected causing a short-circuit.